Process for bleaching montan wax



l atent ed June 24, 193(l @UNITED STATES ,PATENTOFFICE mnnonon HELLTH/ALER, oFsnANscHUTz, GERMANY, Assrenon TO THE FIR-M A. RIE- rmx'scmi 'MONTANWERKE AKTIENGESELLSCHAFT,.OF anna, SAALE; GERMANY rnoenss non BLEACI-IING MONTAN wAx No Drawing. Application filed July 18, 1927, Serial No. 206,799, and'in Germany July 26, 1926;

This invention relates to the process of bleaching so-called montan wax. This mineral in chemical and physicalrespect resembles vegetable waxes, for instance carnauba wax. However thedark color of the montan wax isagreat draw-back in comparison with vegetable waxes- Many attempts have been madeto effect the bleaching of montan wax by physicaland chemical treatment. Upto-date the wax isvdistilled in vacuo with superheated steam whereby a clear product is obtained; however,the output is quite unsatisfactory, and besides the chemical composition of the distillate differs from that of the raw material to a considerable extent. Therefore further trials were made to refine the montan wax solely by chemicalmeans, but the outputs of such methods were likewise very small owing to the extensive formation of resins. I

.It has recently been proposed to bleach montan wax by chromic acid in presence of glacial acetic acid. With this oxidant it is possible to obtain a. satisfactoryoutput of a, clear product which substantially conserves the character of the; original wax.

However, the relatively high'price of glacial acetic acid as well as its unpleasant properties prevent a general application of this process which is therefore not carried out on an industrial scale. I

Now I- have found that montan wax can alsobe bleached by treating it with toxidants such as hydrogen peroxide, chromic acid or an alkali metal bichromate in presence of diluted sulfuric acid. When stirring montan wax in the molten state with oxidants in presenceiof diluted acid, the wax is strongly swelledup and'emulsified in the diluted acid. In the state of distribution the montan wax offers the oxidants a sur face of attack which otherwise only exists,

in the state of real solution, Suitable concentrations a'IId'QOIIdltIOIIS of working are described in the examples given at the end:

of the specification However, my invention is not Qconfined' to these conditions which maybe varied within wide limits without departing from the scopeof -my invention.

: After the darkening constituents of the montan wax have been oxidized, the cleared montan wax and the sulfuric acid separate into two distinct layers from which the upper, consisting of wax may easily be re moved. ;v Asthe resinous constituents of .the raw montan wax are violently attacked by the oxidizing agent, whereby less valuable products are formed, it is advisable to separate the resins from the montan wax by any known process before the oxidative' treatment, especially when a montan wax rich in resins is to be treated. The preliminary separation of the resins affords the further advantage of saving oxidizing agents. As a result thethickening phenomena which disturb theuniform action of the oxidizing liquorwand which otherwisecan be avoided only with difficulty arereducedto a mini mum. V t In order to obtain products having special properties,-the single constituents of the montan wax obtained by fractionating the wax by meansof organic solvents, for instance the particularly valuable and easily clearable wax esters, may. be treated according to my present invention, instead of using. the .7 whole or refined montan wax. In the same. manner thewax alcohols and acids obtained by saponifying montan wax or the products obtained by transforming, these substances may be subjected to the bleaching process."

The degree of clearing produced by my i r present process depends of course upon the constitution of the raw material, the amount of the oxidant employed and the method fresh. oxidative mixture until the desired I bleaching effectis attained. In this way the oxidant willibe completely utilized and, at thesame time, ahigh bleachingeifectob- 'tained. 1 v

' Rational and uniform oxidation may further be favoured by the addition of inertinorganic or organic distributers. For this purpose solid substances such as silica or, earths, as well as especially inert liquid Wax solvents, for instance carbon tetrachloride, may be used. These solvents are also suitable for checking the thickening phenomena which readily occur during the oxidation. Of course, the distributers must be removed from the bleached wax by allowing them to set or by filtering or distilling.

After being treated with diluted sulfuric acidthe wax still retains a certain amount of sulfuric acid 'or reduced oxidant. For instance, when employing chromic acid as oxidant, the cleared wax is colored green by a chromic sulfate solution. For further refinement the wax may be treated in the molten'state with diluted acids and finally with water. If required, the'last remnants of coloring contaminations may be removed by treating the wax either molten: or dissolved in a suitable solvent such as benzene, benzine, carbon tetrachloride with small quantities of an absorbent, for instance, floridine, color removing carbon or the like. The output of products cleared according to my new process amounts to 88-96%. The products retain, their valuable physical properties and are of a light-yellow to white color, which depends upon the amount of the oxidant employed. The high fusing point so important for the value is conserved or even increased underthe oxidative treatment provided the oxidation is. not overdone.

' The sulfuric solution of the consumed oxidant obtained by the; present process may he reoxidized in the well-known manner and then re-used.

Exam Zes 1'. 500 gramsof raw black-colored nion tan wax are melted and mlxed with a solution of 1250 grams of concentrated sulfuric acid in 680 grams of water. With continuous stirring a solution of 500 grams of sodiv um bichroinate in 500 grams of waterfis added within lhours. Stirring is continued until'the solution has. become dark green. After stopping the stirrer the oxidized wax rises to the top of the chromic liquor and is removed. After melting and washing with a '10% sulfuric acid and finally with water a yellow wax is obtained, the output amounting to 90%.

2. The same operations as in the foregoing example, but using a montan wax freed from resins in the well-known manner. A

yellow wax is obtained. 7

Raw montan wax'is saponified and the non-saponifiable part removed from the soaps by avolatile solvent. The non-sapon V V ifiable part forms a substance yellow as 'wax and'fusing at 77 It may be further cleared up by oxidation as above described. 1 The dark brown wax acids obtained by decomposing the soaps with mineral acids are converted, according to the foregoing matter from the wax and then treating the,

wax with an oxidant in presenceof mod; erately diluted sulfuricacid.

3. Process for; bleachingmontan wax which comprises isolating the constituents of the wax by means of solvents, and sep arately treating the said cofnstituentswith' an oxidant 111' presence of, moderately diluted sulfuric acid. is

l. Process for bleaching montan wax which comprises treating the wax partially exhausted and then with a fre'shoxidant in presence of moderately diluted sulfuric acid. I

5. Process for bleaching montan wax which comprises treating the wax with an oxidant in presence of moderately diluted sulfuric acid and a distributing medium.

6. Process for bleaching montan wax which comprises treating the wa'xWith an oxidant in presence ofmoderately diluted sulfuric acid and washing the product with a diluted acid and thereafter with water.

7'. Process for bleaching montan wax which comprises treating the Wax with an oxidant in presence of moderately diluted sulfuric acid, dissolving the'product in' the presence of'a decolorizing solid absorbent, separating the solution from'thes'aid solid adsorbent, and removing the solvent em- 5 ployed.

8. Process for bleaching montan wax which comprises isolating the constituents of the wax by means of solventd'separately treating the said constituents with an oxidant in presence of moderately diluted sulfuric acid, dissolving the product in an inert organic solvent in the presence of ads colorizing solid absorbent, separating the solution from the said solid absorbenhand removing the solvent employed.

9. Process for: bleaching montan wax which comprises treating the waxwith an oxidant in presence of diluted sulfuric acid containing about 65% 'H SO lO. Process forbleaching montan wax which comprises extracting the resinous matter from thewaxand then treating the wax with anoxidant in presence of diluted sulfuric acid containing about 65% 'H' S O ioo 11. Process for bleaching montan wax which comprises fractionatin the constituents of the wax by means solvents, and separately treating the said constituents with an oxidant in presence of diluted sulfuric acid containing about 65% H 60 12. Process for bleaching montan wax which comprises treatingthe wax with a partially exhausted and then with a fresh oxidant in presence of diluted sulfuric acid containing about 65% H SO 13. Process for bleaching montan wax which comprises treating the wax with an oxidant in presence of diluted sulfuric acid containing about 65% H SO and a distributing medium.

14. Process for bleaching montan wax which comprises treating the wax with an oxidant in presence of diluted sulfuric acid containing about 65% H 80 and washing the product with a diluted acid and thereafter with water; i

15. Process for bleaching montan Wax which comprises treating the wax with an oxidant in presence of diluted sulfuric acid containing 65%I-I 'SO dissolving the product in an inert organic solvent in the presence of a decolorizing solid absorbent, separating the solution from the said solid absorbent, and removing the solvent employed. s v

16. Process for bleaching montan wax which comprises fractionating the constituents ofthe wax by means of solvents, separately treating the said constituents with an oxidant in presence of diluted sulfuric acid containing about 65% H SO dissolving the product in an inert organic solvent in the presence of a decolorizing solid absorb- 40 ent, and removing the solvent employed.

17. Process for bleaching montan' Wax which comprises treating the wax with an oxidant in presence of diluted sulfuric acid containing about 65% H 80 dissolving the product in the presenceof a decolorizing solid absorbent, separating the solution from the said solid absorbent, and removing the solvent employed.

18. Process for bleaching montan wax which comprises fractionating the constituents of the wax by means of solvents, separately treating the said constituents with an oxidant in presence of diluted sulfuric acid containing about H dissolv- 55 ing the product in an inert organic solvent in the presence of a decolorizing solid ab sorbent, separating the solution from the said solid absorbent, and removing the solvent employed. 7 so In testimony whereof I aflix my signature.

THEODOR HELLTHALER. 

